A charging device for a battery pack includes a preferably closed housing and has an external charging receptacle for a battery pack. In the charging receptacle—normally in the region of a face wall—there are provided electrical connection contacts for the electrical contacting of a battery pack to be inserted. The charging device is formed with an electrical connector for a supply voltage, wherein, between the electrical connector and the connection contacts to the battery pack, there are arranged parallel electronics by way of which the battery pack is electrically charged.
For the dissipation of the heat generated during the charging process, a cooling air fan is arranged in the housing of the charging device, to which cooling air fan a cooling air stream flows, as a suction air stream, via an air inlet opening, the cooling air stream exiting the housing via an air exit opening. Via the air inlet opening, a battery air stream which flows through the battery pack is supplied as a cooling air stream, the cooling air stream also being utilized for cooling the components of the power electronics.
The waste heat generated during the charging of the individual cells in the battery pack leads to an increase in temperature of the cooling air stream, such that the cooling air stream can absorb and discharge only a small amount of heat as it flows around the power electronics. The temperature difference, required for cooling the power electronics, between the cooling air stream and the electronic components of the power electronics is thus dependent on the temperature increase to which the battery air stream is subjected as it flows through the battery pack. In the case of rapid-charging devices or battery packs of large capacity, the cooling of the power electronics may become inadequate.